 (defn builder [data owner]
   [:p "hello, i've been built by a builder"])
 
-(def buf1 (buffer 10))
+(def bufsize 7)
+
+(def buf1 (buffer bufsize))
 (def chan1 (chan buf1))
 
 (defn diagram-1 [data owner]

                          (om/set-state! owner :modified (new js/Date))
                          ))
             } ">!"]
   [:button {:style {:font-size "60pt"}
             :onClick (fn [_]
                        (go
                          (<! chan1)
                          (om/set-state! owner :modified (new js/Date))))
             } "<!"]
   [:svg {:version "1.1" :width 600 :height 600}
    [:text {:x 200 :y 100} "(>! (chan))"]
    (for [x (range 10)]
      [:g
       [:rect {:x (* 60 x) :y 0 :width 40 :height 40 :style {:fill "blue"}}]
       [:text {:x (* 60 x) :y 20} (str "h" (aget (.-arr (.-buf buf1)) x))]]
      )
    ]])

(def app-model
  (atom {:current-slide 5

          {:title "Diagram"
           :builder builder
           }
          {:title "put and take"
           :builder diagram-1
           }
          {:title "When?"
